Journal of Geophysical Research: Space Physics最新文献

{"title":"Controlling Factors of Chorus Spectral Gaps","authors":"Jinxing Li,&nbsp;Jacob Bortnik,&nbsp;Wen Li,&nbsp;Xin An,&nbsp;Larry R. Lyons,&nbsp;William S. Kurth,&nbsp;George B. Hospodarsky,&nbsp;David P. Hartley,&nbsp;Geoffrey D. Reeves,&nbsp;Herbert O. Funsten,&nbsp;J. Bernard Blake,&nbsp;Harlan Spence,&nbsp;Daniel N. Baker","doi":"10.1029/2023JA031893","DOIUrl":"https://doi.org/10.1029/2023JA031893","url":null,"abstract":"<p>The present study compares a single-band chorus wave against a banded chorus wave observed by Van Allen Probes at adjacent times, and demonstrates that the single-band chorus wave is associated with an anisotropic electron population over a broad energy range, while the banded chorus wave is accompanied by an electron phase space density plateau and an electron anisotropy reduction around Landau resonant energies. We further compare banded chorus waves with different spectral gap widths, and show that a wider spectral gap is associated with electron isotropization extending to higher energies with respect to the equatorial Landau resonant energy. We suggest that early generated chorus waves isotropize electrons via Landau resonant acceleration, and the waves that propagate to higher latitudes isotropize electrons at higher energies. The isotropization extending to higher energies leads to a larger spectral gap of new chorus waves after electrons bounce back to the equator.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2023JA031893","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of Co-Seismic Ionospheric Perturbations Generated by Shallow Earthquakes in the Chile Subduction Zone","authors":"Subrata Kundu,&nbsp;Mala S. Bagiya","doi":"10.1029/2024JA032676","DOIUrl":"https://doi.org/10.1029/2024JA032676","url":null,"abstract":"<p>The Chile subduction zone is known to host megathrust earthquakes. This study investigates the near-field co-seismic ionospheric perturbations (CIP) associated with recent large to great, shallow depth (22–25 km) earthquakes that occurred in the Chile subduction zone. These earthquakes are (a) 16 September 2015, Mw 8.3 (EQ1) (b) 03 April 2014, Mw 7.7 (EQ2) (c) 01 April 2014, Mw 8.2 (EQ3) (d) 02 January 2011, Mw 7.1 (EQ4), and (e) 27 February 2010, Mw 8.8 (EQ5). Using the Global Navigation Satellite System (GNSS) measured total electron content (TEC), we found that despite the lower magnitude of EQ3 than EQ1 and EQ5, the CIP observed during EQ3 had higher amplitudes than that of EQ5 and EQ1. The amplitude of CIP also depends on non-seismic parameters in addition to the concerning earthquake magnitude. The comparison of relative CIP amplitudes, in light of the non-seismic parameters of the geomagnetic field and satellite geometry indicates that background electron density (due to different local times of earthquake occurrence) might contributed to CIP amplitudes. We believe that this thorough analysis leads to a better understanding of non-seismic factors that can largely influence the CIP amplitudes apart from the earthquake magnitudes.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328495","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of Interplanetary Shock on Thermospheric Cooling Emission: A Case Study","authors":"Tikemani Bag,&nbsp;V. Sivakumar,&nbsp;Y. Ogawa","doi":"10.1029/2024JA033176","DOIUrl":"https://doi.org/10.1029/2024JA033176","url":null,"abstract":"<p>Interplanetary (IP) shock is one of the most common phenomena that controls the shape and size of the magnetosphere. It affects the whole magnetosphere-ionosphere-thermosphere (MIT) system. We utilized the NO 5.3 <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>μ</mi>\u0000 </mrow>\u0000 <annotation> ${upmu }$</annotation>\u0000 </semantics></math>m radiative emission, as observed by SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) onboard NASA's TIMED (Thermosphere Ionosphere Mesosphere Energetics Dynamics) satellite, to investigate its response to fast forward shock during 26 January 2017. The high latitude NO emission exhibits a strong enhancement (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>∼</mo>\u0000 </mrow>\u0000 <annotation> ${sim} $</annotation>\u0000 </semantics></math>three times with respect to pre-event value) during IP shock within 5 hr of onset. We analyzed both the energy dissipation sources and subsequent chemical mechanisms. The Field-Aligned-Current observations from Active Magnetosphere and Planetary Response Experiment (AMPERE), EISCAT measurements of Pederson conductivity and the defense Meteorological Satellite Program (DMSP F18) calculated hemispheric power demonstrate a strong intensification. The low energy particle precipitation from DMSP F18 spacecraft shows an early enhancement for energy less than 1 keV. The particle flux of higher energy responds later which remained elevated for longer duration. The thermospheric density and temperature also experience significant variation during IP shock. The NO molecule and temperature displayed an early enhancement. NO density increased by an order of magnitude with respect to the pre-event value. About 20<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mi>%</mi>\u0000 </mrow>\u0000 <annotation> $%$</annotation>\u0000 </semantics></math> increase is noticed in the temperature variation. The atomic oxygen and atomic nitrogen illustrate an early depletion during IP event. The enhanced response of NO cooling to IP shock can be attributed to the combined effects of energy input and subsequent chemical mechanisms.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142328496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Outer Zone Relativistic Electron Response to Mesoscale Periodic Density Structures in the Solar Wind: Van Allen Probes Measurements","authors":"Leenamol V. Kurien,&nbsp;Shrikanth G. Kanekal,&nbsp;Simone Di Matteo,&nbsp;Ashley D. Greeley,&nbsp;Quintin Schiller,&nbsp;Mykhaylo Shumko,&nbsp;Nicholeen M. Viall,&nbsp;Emil Lawrence Kepko","doi":"10.1029/2024JA032614","DOIUrl":"https://doi.org/10.1029/2024JA032614","url":null,"abstract":"<p>We investigate the relativistic and the ultra-relativistic outer radiation belt electron response to the Periodic Density Structures (PDS) in the solar wind. We have studied four intervals between 0000 UT and 1500 UT during 17 January 2013 interplanetary coronal mass ejection (ICME) sheath event following the passage of an interplanetary shock (IP) on 16 January, at 2240 UT. Earlier studies limited to geosynchronous orbit have shown that PDS induce Ultra-Low-Frequency (ULF) oscillations in the magnetosphere and modulate energetic electron intensities. Our study shows for the first time, using pitch angle resolved electron intensity measurements, that PDS modulate relativistic and ultra-relativistic electron intensities in the heart of the radiation belts (<i>L</i> ≈ 4). We find that the modulation of electron intensities occur at frequencies close to those of interplanetary PDS. Furthermore, electron intensity modulations occur over a wide range of energy (≈200 keV to 4 MeV) and pitch angles (≈20–120°). This event study suggests that relativistic and ultra-relativistic electron intensity modulations driven by PDS may be largely energy and pitch angle independent.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA032614","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142324448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of the October 14, 2023, Ring of Fire Annular Eclipse on the Ionosphere: A Comparison Between GNSS Observations and SAMI3 Model Prediction","authors":"Sayak Ray,&nbsp;J. D. Huba,&nbsp;Bhaskar Kundu,&nbsp;Shuanggen Jin","doi":"10.1029/2024JA032710","DOIUrl":"https://doi.org/10.1029/2024JA032710","url":null,"abstract":"<p>Celestial phenomena such as solar eclipses disrupt the ionosphere's inherent photochemical, dynamic, and electrodynamic processes and can be viewed as a natural experiment that provides a unique opportunity to study ionospheric perturbations. We investigate the spatiotemporal ionospheric response induced by the 14 October 2023 annular eclipse using ground-based Global Navigation Satellite System (GNSS) receivers located over the continental region of North and South America. The largest total electron content (TEC) change (∼22 TECU decrease) is observed over the path of the eclipse at around 16°–18°N which lies just before the greatest eclipse location. However, the percentage change in TEC here is ∼44% (of the background value), which is less than that observed at midlatitudes around 30°–35°N (∼18.7 TECU, ∼50%). We observed a latitudinal dependency of TEC variation and time delay in ionospheric response to the eclipse with midlatitudes experiencing greater TEC changes and longer time delays compared to low-latitude and equatorial regions. The SAMI3 model used to simulate the impact of the eclipse, captures the large decrease in VTEC along the eclipse path. Interestingly, increases in the TEC are also observed in several GNSS sites and it varied from 4.5 to 6.5 TECU in the Northern Hemisphere and 7 to 12 TECU in the Southern Hemisphere. The SAMI3 model results also show an enhancement in TEC but significantly less than that observed. Moreover, the SAMI3 model simulations for individual GNSS site coordinates within the conjugate regions failed to predict accurately, the TEC enhancement recorded by the GNSS sites.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142320865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Role of Physical Processes in Controlling Equatorial Plasma Bubble Morphology","authors":"G. A. S. Picanço,&nbsp;C. M. Denardini,&nbsp;P. A. B. Nogueira,&nbsp;P. R. Fagundes,&nbsp;A. M. Meza,&nbsp;L. P. O. Mendoza,&nbsp;M. B. Pádua,&nbsp;M. P. Natali,&nbsp;L. C. A. Resende,&nbsp;L. F. R. Vital","doi":"10.1029/2024JA032756","DOIUrl":"https://doi.org/10.1029/2024JA032756","url":null,"abstract":"<p>In this study, we present the results of an analysis of the morphological features of Equatorial Plasma Bubbles (EPBs) over South America. In this context, we analyzed data from the Disturbance Ionosphere indeX (DIX) maps calculated using around 450 Global Navigation Satellite System (GNSS) stations. To mitigate the influence of magnetic disturbances on bubble development, only data from geomagnetically quiet days were utilized. This study covered the period from the post-peak of solar cycle 24 (2015) to the pre-peak of solar cycle 25 (2023), totaling 1321 nights with EPB occurrences, representing the largest data set of EPBs ever compiled for South America. Our analysis unveiled several key findings regarding EPBs and their behavior over the South American region. First, we observed that the amplitude of plasma depletions, as reflected in the DIX values, and the EPB latitudinal development follow an approximately 11-year cycle driven by solar radiation levels. Furthermore, our analysis highlights the significant influence of factors such as the angle between the solar terminator and the magnetic meridian (T-M angle), which varies inversely with the vertical plasma drift velocity during the pre-reversal enhancement (PRE). Additionally, we discuss the longitudinal variations associated with magnetic declination, as well as the saturation behavior of EPB development with extreme solar flux.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142320860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surface Charging of the Jupiter Icy Moons Explorer (JUICE) Spacecraft in the Solar Wind at 1 AU","authors":"M. K. G. Holmberg,&nbsp;C. M. Jackman,&nbsp;M. G. G. T. Taylor,&nbsp;O. Witasse,&nbsp;J.-E. Wahlund,&nbsp;S. Barabash,&nbsp;B. Michotte de Welle,&nbsp;H. L. F. Huybrighs,&nbsp;C. Imhof,&nbsp;F. Cipriani,&nbsp;G. Déprez,&nbsp;N. Altobelli","doi":"10.1029/2023JA032137","DOIUrl":"https://doi.org/10.1029/2023JA032137","url":null,"abstract":"<p>This article presents the first study of the interaction between the Jupiter Icy Moons Explorer (JUICE) spacecraft and the solar wind environment at 1 AU. The state-of-the-art software Spacecraft Plasma Interaction Software was used to simulate the surface charging of the spacecraft and the altered particle environment around the spacecraft. The simulations show that for a typical solar wind environment the spacecraft will charge to around 6 V, with the different dielectric parts of the spacecraft charging to potentials from around −36 to 8 V. For the studied extreme solar wind environment, similar to the environment found in the sheath region inside the shock front of an Interplanetary Coronal Mass Ejection, the surface potential of the spacecraft is lower due to the increased accumulation of electrons. The spacecraft will charge to around 3 V, with the different dielectric surfaces charging from around −45 to 9 V. We also show how the interaction between the spacecraft and its environment alters the ion and electron particle environment around the spacecraft. This study is the first step toward developing correction techniques for the impact that the interaction between the JUICE spacecraft and its environment has on the JUICE charged particle and field measurements.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two-Spacecraft Observations of Asymmetric Martian Bow Shock: Conjunctions of Tianwen-1 and MAVEN","authors":"Long Cheng,&nbsp;Yuming Wang,&nbsp;Robert Lillis,&nbsp;Jasper Halekas,&nbsp;Benoit Langlais,&nbsp;Tielong Zhang,&nbsp;Jacob R. Gruesbeck,&nbsp;David L. Mitchell,&nbsp;Shannon Curry","doi":"10.1029/2024JA033185","DOIUrl":"https://doi.org/10.1029/2024JA033185","url":null,"abstract":"<p>The Martian bow shock has been extensively studied through magnetic field and plasma instrument observations from various Mars space missions. However, prior investigations primarily involve statistical analyses based on single spacecraft crossings, leaving the asymmetry of the Martian bow shock unstudied through simultaneous two-spacecraft observations. In this study, utilizing simultaneous observations from Tianwen-1 and MAVEN, we examine the instantaneous asymmetry of the Martian bow shock. We present the asymmetry of the Martian bow shock in the Mars-Solar-Electric and Mars-Solar-Orbital reference frames, possibly influenced by the solar wind motional electric field and Martian crustal magnetic field, respectively. Moreover, we suggest that the bow shock exhibits increased asymmetry under stronger solar wind motional electric field conditions. This study highlights how a two-point observation approach offers valuable insights into the dynamic behavior of the Martian induced magnetosphere.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA033185","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Multi-Scale Particle-In-Cell Simulation of Plasma Dynamics From Magnetotail Reconnection to the Inner Magnetosphere","authors":"L. Rusaitis,&nbsp;M. El-Alaoui,&nbsp;R. J. Walker,&nbsp;G. Lapenta,&nbsp;D. Schriver","doi":"10.1029/2024JA032821","DOIUrl":"https://doi.org/10.1029/2024JA032821","url":null,"abstract":"<p>During magnetospheric substorms, plasma from magnetic reconnection in the magnetotail is thought to reach the inner magnetosphere and form a partial ring current. We simulate this process using a fully kinetic 3D particle-in-cell (PIC) numerical code along with a global magnetohydrodynamics (MHD) model. The PIC simulation extends from the solar wind outside the bow shock to beyond the reconnection region in the tail, while the MHD code extends much further and is run for nominal solar wind parameters and a southward interplanetary magnetic field. By the end of the PIC calculation, ions and electrons from the tail reconnection reach the inner magnetosphere and form a partial ring current and diamagnetic current. The primary source of particles to the inner magnetosphere is bursty bulk flows (BBFs) that originate from a complex pattern of reconnection in the near-Earth magnetotail at <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msub>\u0000 <mi>x</mi>\u0000 <mtext>GSM</mtext>\u0000 </msub>\u0000 <mo>=</mo>\u0000 <mo>−</mo>\u0000 <mn>18</mn>\u0000 <msub>\u0000 <mi>R</mi>\u0000 <mi>E</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${x}_{text{GSM}}=-18{R}_{mathrm{E}}$</annotation>\u0000 </semantics></math> to <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>30</mn>\u0000 <msub>\u0000 <mi>R</mi>\u0000 <mi>E</mi>\u0000 </msub>\u0000 </mrow>\u0000 <annotation> ${-}30{R}_{mathrm{E}}$</annotation>\u0000 </semantics></math>. Most ion acceleration occurs in this region, gaining from 10 to 50 keV as they traverse the sites of active reconnection. Electrons jet away from the reconnection region much faster than the ions, setting up an ambipolar electric field allowing the ions to catch up after approximately 10 ion inertial lengths. The initial energy flux in the BBFs is mainly kinetic energy flux from the ions, but as they move earthward, the energy flux changes to enthalpy flux at the ring current. The power delivered from the tail reconnection in the simulation to the inner magnetosphere is <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mo>&gt;</mo>\u0000 <mn>2</mn>\u0000 <mo>×</mo>\u0000 <mn>1</mn>\u0000 <msup>\u0000 <mn>0</mn>\u0000 <mn>11</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${ &gt;} 2times 1{0}^{11}$</annotation>\u0000 </semantics></math> W, which is consistent with observations.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142313371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generation of Field-Aligned Currents in Response to Sudden Enhancement of Solar Wind Dynamic Pressure","authors":"Tian Zhang,&nbsp;Yusuke Ebihara,&nbsp;Takashi Tanaka","doi":"10.1029/2024JA032768","DOIUrl":"https://doi.org/10.1029/2024JA032768","url":null,"abstract":"<p>We investigated the generation of field-aligned currents (FACs) in response to the sudden enhancement of the solar wind dynamic pressure by tracing backward in time a packet of the Alfvén wave in the global magnetohydrodynamic (MHD) simulation. The generation region is identified from three perspectives, including the continuity of the current, the energy conservation and the time rate of change in the FACs. The generation mechanism is found to be related with the tailward motion of the compressional wave, which is excited when the magnetopause is compressed due to the solar wind dynamic pressure pulse. The compressional wave with a high magnetic pressure center interacts with the Earth's dipole field and forms a protruding part of the wavefront near the equatorial plane. The leading edge of the merged magnetic pressure that pertains to the compressional wave and the Earth starts to generate preliminary impulse (PI) FACs off the equator, as the magnetic pressure force accelerates the plasma and magnetic field lines are bent (FAC dynamo 1). Main impulse (MI) FACs are generated behind the leading edge in the equatorial plane due to the enhanced magnetic tension force (FAC dynamo 2). Magnetic field lines would be extremely curved during the passage due to the increasing magnetic tension force. The polarity of PI FACs is decided by the parallel vorticity of plasma flow, and MI FACs are the result of enhanced perpendicular currents together with the plasma flow in the equatorial plane.</p>","PeriodicalId":15894,"journal":{"name":"Journal of Geophysical Research: Space Physics","volume":null,"pages":null},"PeriodicalIF":2.6,"publicationDate":"2024-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JA032768","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142276620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}